Ventilation apparatus

ABSTRACT

A method of ventilating a patient controls an actuator, in accordance with a prescribed value for a respiratory parameter, to compress an inflatable bag to cause air to flow out of an output valve of the bag. The respiratory parameter may include tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate of the air flowing through the output valve. The method also senses the pressure flowing through the output valve, and sends a pressure signal to the controller. Additionally, the method senses the flow rate through the output valve, and sends a flow rate signal to the controller. The method also adjusts the compression of the actuator as a function of the flow rate signal and/or the pressure signal to adjust the output tidal volume, pressure, volume limit, peak pressure, I:E ratio, inspiratory time, and/or breathing rate to be in accordance with the prescribed value.

PRIORITY

This patent application claims priority from provisional U.S. patentapplication No. 62/666,403, filed May 3, 2018, entitled, “VENTILATIONAPPARATUS,” and naming Shaheer Ahmed Piracha as inventor, the disclosureof which is incorporated herein, in its entirety, by reference.

FIELD OF THE INVENTION

Illustrative embodiments of the invention generally relate toventilation devices and, more particularly, the various embodimentsrelate to systems and methods for precisely ventilating a patient inaccordance with prescribed parameters.

BACKGROUND OF THE INVENTION

Respiratory disease is one of the leading causes of death in manydeveloping countries. Frequently, there is a shortage of life savingequipment, like ventilators, at hospitals in these countries. As aresult, caregivers are often provided with a bag valve mask or Ambu bagand asked to manually ventilate a patient by hand for hours andsometimes days. This arrangement is unreliable can may be lifethreatening to the patient.

SUMMARY OF VARIOUS EMBODIMENTS

In accordance with one embodiment of the invention, a system ventilatesa patient. The system includes a bag that is configured to be inflatedthrough an input valve that allows oxygen and/or air to flow into thebag. The bag is further configured to be deflated through an outputvalve that allows the oxygen and/or the air to flow out of the bag. Thesystem also includes an actuator configured to compress the bag to causethe oxygen and/or the air to flow out of the output valve in accordancewith prescribed values for one or more respiratory parameter. The one ormore respiratory parameter includes tidal volume, pressure, volumelimit, peak pressure, I:E ratio, inspiratory time, and/or breathing rateof the oxygen and/or the air flowing through the output valve to apatient. The system also has a controller configured to control theposition of the actuator and/or the speed at which the actuator moves inaccordance with the prescribed values for the respiratory parameter.Furthermore, the system includes a pressure sensor coupled to the outputvalve and configured to determine the pressure of the oxygen and/or theair flowing through the output valve. The pressure sensor is furtherconfigured to send a pressure signal to the controller. The system alsoincludes a flow rate sensor coupled to the output valve and configuredto determine the flow rate of the oxygen and/or the air flowing throughthe output valve. The flow rate sensor is further configured to send aflow rate signal to the controller. The controller is configured toreceive the pressure signal and/or the flow rate signal, and todetermine whether the output tidal volume, pressure, volume limit, peakpressure, I:E ratio, inspiratory time, and/or breathing rate are inaccordance with the prescribed values. Additionally, the controller isfurther configured to adjust the position of the actuator and/or thespeed at which the actuator moves so as to adjust the output tidalvolume, peak pressure, and/or breathing rate to be in accordance withthe prescribed values.

In some settings, the bag may be an Ambu bag. The bag may be compressedin accordance with respiratory parameters that include an inhale toexhale ratio. To that end, the bag may be compressed between the paddleand a flat surface. Furthermore, the flat surface may be a fixedsurface. In some embodiments the actuator has a convex contact surfacethat compresses the bag. Furthermore, the bag may have a longitudinalaxis, and the convex contact surface may be configured to extend alongthe longitudinal axis. The system may perform a calibration process toconfirm that the bag is outputting air in accordance with one or moreprescribed respiratory parameter.

Among other things, the actuator may include a spindle that isconfigured to tighten a strap. The strap may be coupled to a paddlehaving the convex contact surface. The strap may have a first end thatis fixed, and a second end that is movable.

In some embodiments, the system is configured to operate in a volumecontrol mode. The volume control mode includes a prescribed value forthe tidal volume, and a prescribed limit for the peak pressure.Alternatively, the system may be configured to operate in a pressurecontrol mode. The pressure control mode includes a prescribed value forthe pressure, and a prescribed volume limit. Among other things, analert may be trigged and/or the actuator may cease ventilating thepatient when the prescribed limit is exceeded.

Additionally, or alternatively, to the flow rate sensor and/or thepressure sensor, the system may also have an oxygen sensor. Each of thesensors may be coupled to a display that shows information relating tothe sensor. In some embodiments, the display may be coupled to a userinput that allows the user to adjust the oxygen input.

In accordance with yet another embodiment, a method ventilates apatient. The method includes controlling an actuator, in accordance witha prescribed value for a respiratory parameter, to compress aninflatable bag to cause oxygen and/or air to flow out of an output valveof the bag. The respiratory parameter may include tidal volume,pressure, volume limit, peak pressure, I:E ratio, inspiratory time,and/or breathing rate of the oxygen and/or the air flowing through theoutput valve. The method also senses the pressure flowing through theoutput valve, and sends a pressure signal to the controller.Additionally, the method senses the flow rate through the output valve,and sends a flow rate signal to the controller. The method also adjuststhe compression of the actuator as a function of the flow rate signaland/or the pressure signal to adjust the output tidal volume, pressure,volume limit, peak pressure, I:E ratio, inspiratory time, and/orbreathing rate to be in accordance with the prescribed value.

In some embodiments, the method couples the actuator to a paddle havinga longitudinal axis. Additionally, the method may substantially alignthe longitudinal axis of the paddle with a longitudinal axis of the bag.Furthermore, the method may adjust the compression of the actuator byadjusting the position of the actuator and/or the speed at which theactuator moves.

Illustrative embodiments of the invention are implemented as a computerprogram product having a computer usable medium with computer readableprogram code thereon. The computer readable code may be read andutilized by a computer system in accordance with conventional processes.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art should more fully appreciate advantages ofvarious embodiments of the invention from the following “Description ofIllustrative Embodiments,” discussed with reference to the drawingssummarized immediately below.

FIG. 1 schematically shows a ventilation device connected to a patientand a mobile application in accordance with illustrative embodiments ofthe invention.

FIG. 2 schematically shows the internal components of the device inaccordance with illustrative embodiments of the invention.

FIGS. 3A-3C schematically show views of a paddle for compressing aventilation bag in accordance with illustrative embodiments of theinvention.

FIG. 4 schematically shows a block diagram of a system that uses theventilation apparatus in accordance with illustrative embodiments of theinvention.

FIG. 5 schematically shows details of the controller that receivesfeedback from the one or more sensors and that controls the output ofthe motor in accordance with illustrative embodiments of the invention.

FIG. 6 shows one embodiment of a process of ventilating the patient inaccordance with prescribed values for respiratory parameters.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In illustrative embodiments, a ventilation apparatus provides reliableand precise ventilation to a patient in accordance with a set ofprescribed respiratory parameters. The apparatus operates on aninflatable bag used to provide positive pressure ventilation to patientswho are not breathing adequately. For example, the apparatus may operatewith a bag valve mask (also referred to under the proprietary name “Ambubag”). The operator is allowed to select values for one or morerespiratory inputs. Sensors measure the output from the bag, and providea feedback loop to a controller, which makes corresponding adjustmentsto an actuator. The actuator has a convex shaped contact surface and isoriented parallel to the longitudinal axis of the bag. Details ofillustrative embodiments are discussed below.

FIG. 1 schematically shows the ventilation device 12 and a patient 13 inaccordance with illustrative embodiments of the invention. Theventilation device 12 may have a housing 14 that contains the internalcomponents. The housing 14 may have two openings 16A and/or 16B thataccommodate two valves 21A and 21B, one for air input, and the other forair output, respectively. Preferably, each of these valves 21A and 21Bis a one-way valve (e.g., input valve 21A only allows airflow into thedevice 12, output valve 21B only allows airflow out of the device 12).However, in some embodiments, the one-way valve 21B may additionally, oralternatively, be on the bag (see, for example, FIG. 2). Thus, theopenings 16A and/or 16B may accommodate tubing that is part of abreathing circuit including the one-way valves 21A and 21B.

In FIG. 1, with the air input opening 16A is on the front side of thehousing 14, and the air output opening 16B is on the side of the housing14. It should be understood however that illustrative embodiments mayhave the openings 16A and 16B in various arrangements and orientationsnot shown herein, and are not intended to be limited to the arrangementshown herein. Although the term “air” is used with reference to thedevice 12, it should be understood that illustrative embodiments may usepure oxygen, or various gas combinations not found in the ambient air.Accordingly, the term “air” is not intended to limit illustrativeembodiments to use only with ambient air in the environment. Indeed, theterm “air” may include, among other things, pure oxygen provided by acommercial gas supplier.

The device 12 may be used in hospital or non-hospital settings, such aswhere the patient is laying on a hospital bed 18, emergency transport,in-field, etc. A breathing tube 22 may couple the output valve 21B tothe patient 13. At the end of the breathing tube 22 may be another oneway valve 24. The one way valve 24 may be similar to the valves 16A-16Bthat are found at the ends of a bag (e.g., the Ambu bag). The valve 24provides one way ventilation that allows air to flow to the patient 13while also preventing back flow of air in to the device 12. Accordingly,the valve(s) 24 and 21B may prevent contamination from entering backinto the device 12. Additionally, illustrative embodiments may use amask 26 and/or endotracheal tube 26 to couple the output valve 21B tothe patient 13. The mask 26 and/or endotracheal tube 26 attaches to theend of one of the breathing tubes and inhibits air from escaping duringthe ventilation inhalation and exhalation cycle. The one way valve 26may also provide for easy addition of a peep valve that is commonly usedin resource-limited hospitals.

Many developing countries do not have an adequate number of ventilatorsfor their patients 13. Instead, hospitals and emergency settings mayrequire the use of the bags. Frequently, medical staff 20 or familymembers may be tasked with ventilating the patient 13 using the bag.However, proper ventilation of the patient 13 requires precise deliveryof a given volume of air, at a given pressure, and at a given tempo fora sustained period of time, which is difficult to achieve even fortrained staff 20.

Furthermore, the staff 20 may not have feedback about the pressure orflow rate that is used to ventilate the patient 13. Delivering airand/or oxygen in accordance with prescribed values for respiratoryparameters is a more effective and safe manner of ventilating patients13. For example, if the patient 13 receives too much tidal volume, thelungs may rupture or collapse. Additionally, if the patient 13 receivestoo much air pressure, the lung could be punctured and the patient 13could have internal bleeding. If the air pressure is too low, the airand/or oxygen may not reach the lungs of the patient 13.

Even if feedback about the output parameters is provided to the staff20, it is nearly impossible to manually ventilate the patient 13consistently for a sustained period of time in accordance with therespiratory parameters. To further complicate matters, the inputparameters for each patient 13 differ based on physiological differencesin the patient 13 (e.g., height, body weight, age, etc.). Thus, evenexperienced staff 20 with feedback may have difficulty ventilating thepatient 13 in accordance with appropriate parameters for a sustainedperiod of time.

Accordingly, illustrative embodiments of the device 12 provide sensorsthat measure the output of the bag, and that provide feedback to acontroller, which automatically adjusts an actuator to ventilate thepatient 13 in accordance with the prescribed parameters. To that end,the device 12 may have a user interface 23, which may include a touchscreen and/or a knob. The operator may enter the desired values tocontrol a variety of respiratory parameters. For example, illustrativeembodiments allow a user 20 to input respiratory parameters, including:Output Volume between about 0 and about 700 ml, Pressure Limit—betweenabout 0 and about 50 mm H₂O, Breathing rate between about 1 and about 30bpm, Inhalation to exhalation ratio of between about 1:0 and about 1:3,inspiratory time of between about 0.5 and about 3 seconds. The userinterface 23 may provide the user secondary controls, including:switching between Pressure Control and Volume Control, changing powersource from battery to power supply, oxygen titration based on % O2reading on the screen, turning on/off Bluetooth, turning on/off Wi-Fi,turning Assist Control on/off. Furthermore, the system 100 may includealarms (e.g., for low battery, high pressure, disconnection of breathingtube) on the device 12, a display, or a mobile electronic device 19.Alarm tells the actuator to stop and go back to the reset position.

In addition to the user interface 23, illustrative embodiments may use amobile electronic device 19 (such as smartphone 19 having a mobile app)to input the respiratory parameters. The values for the respiratoryparameters may also be displayed on the mobile electronic device 19.

FIG. 2 schematically shows the internal components of the device 12 inaccordance with illustrative embodiments of the invention. The device 12may also include wires and electronics not shown herein for convenience.The device 12 may include a base 30 on which the internal componentsrest and/or are mounted. The device 12 includes an inflatable bag, suchas the bag 28 (e.g., an Ambu bag). As described previously, the bag 28may be inflated via air flow coming through input valve 21A.Additionally, the bag 28 may be deflated via air flow exiting throughoutput valve 21B. Specifically, the bag 28 deflates as it is compressedby paddle 32. In some embodiments, the bag 28 is compressed between thepaddle 32 and a flat surface such as the base 30.

As described further below, illustrative embodiments may include just asingle convex contact surface 50 (e.g., a single paddle 32) to avoidcreating dead space that may otherwise result from multi-directionalinward compression (e.g., simultaneous compression from two convexpaddles). For example, compressing the cylindrically shaped body of thebag 28 between two semi-spherical paddles 32 may create unintended deadspace in the top and bottom quadrants of the bag 28. However, some otherembodiments may include more than one paddle 32.

In illustrative embodiments the paddle 32 is coupled with a strap 34. Atone end, the strap 34 may be fastened to the base 30 using a fastener33. At the other end, the strap 34 may be coupled to an actuator that,when activated, tensions the strap 34. Thus, in illustrativeembodiments, a first end of the strap 34 may be fixed, and a second endof the strap 34 may be movable. The inventors were surprised to discoverthat having one end of the strap 34 fixed, and the other end movable,provides the advantage of making the device 12 cleaner, smaller andefficient to drive and control precisely. Additionally, in comparison tomulti-bar linkages, the strap 34 provides a simpler device 12 with lowerrates of failure and easy maintenance. This is a significant advantagein certain markets where resources are limited. Tensioning the strap 34causes the paddle 32 to inwardly radially compress the bag 28. As thebag 28 is compressed, air exits from the output valve 21B and the bag 28deflates. It should be understood that the term deflate does not requirethat the bag 28 completely deflate. Indeed, the bag 28 may partiallydeflate in accordance with prescribed parameters.

In illustrative embodiments, the actuator includes a spindle 36 coupledto a motor 40 through a gear box and adapter 38. The inventorsdiscovered that coupling the paddle 32 to the strap 34, and actuatingcompression of the bag 28 using a spindle 36 provides variousadvantages. For example, a paddle that is movable on a hinge undesirablyputs a lot of load on the motor 40, which makes the device 12 morelikely to fail. Given the emergency settings that the device 12 may beused in, it is desirable to have a robust device 12 that is easy tomaintain, with fewer moving parts and lower rates of failure. Inaddition to requiring that the motor 40 work harder to achieve the sameeffects as illustrative embodiments using the strap 34, in the hingearrangement the motor 40 moves very little to compress the bag asignificant amount. Accordingly, illustrative embodiments using thestrap 34 provide for convenient precision control of the volume of thebag.

Although not shown in FIG. 2, a controller may be coupled to the motor40. The controller receives feedback from one or more sensors, andcontrols the output of the motor 40. For example, illustrativeembodiments may include a flow sensor 42 coupled to the output valve21B. Additionally, or alternatively, the device 12 may include apressure sensor 44 coupled to the output valve 21B. Furthermore, anoxygen sensor 46 may additionally or alternatively be coupled to theoutput valve 21B. Although the various sensors 42, 44, and 46 aredescribed as being coupled to the output valve 21B, it should beunderstood that they may not be directly coupled to the output valve21B. For example, the sensors 42, 44, and 46 may be downstream of thevalve 21B and connected via tubing 48. Accordingly, the sensors 42, 44,and 46 described herein advantageously provide information relating tothe air output from the bag 28. These measurements can be directlycorrelated to specific respiratory parameters.

FIGS. 3A-3C schematically show the paddle 32 in accordance withillustrative embodiments of the invention. Specifically, FIG. 3Aschematically shows a perspective view of the paddle 32. FIG. 3Bschematically shows a left-side view of the paddle 32, and FIG. 3Cschematically shows a top view of the paddle 32. The paddle 32 has acoupling portion 49, through which the paddle 32 is coupled to the strap34. On the other end of the paddle 32 is a contact surface 50 that facesand compresses the bag 28.

The inventors were surprised to find that providing a convex contactsurface 50 resulted in advantages over flat or concave contact surfaces50. For example, a flat paddle 32 deforms the bag in a non-linearmotion, meaning that the patient 13 experiences a sudden jump in flowrate and pressure. Additionally, flat paddles 32 create stressconcentrations at the edges of the paddle and at the folding area of thebag 28. This could lead to faster degradation of the bag 28 and evencritical leaks or tears over longer periods of time. A concave contactsurface 50 leaves a large amount of dead space in the bag 28.Additionally, the concave contact surface 50 also causes a large spikein pressure and flow rate at the beginning of the compression cycle.

Accordingly, illustrative embodiments have a convex contact surface 50.Although the paddle 32 is described as having a convex contact surface50, it should be understood that at least some portion of the surfacearea may be flat. Generally, however, the convex contact surface 50allows for smaller buildup of pressure and flow, which is preferred inclinical settings. The convex contact surface 50 generally provides moreprecise deformation/compression of the bag 28, and leaves less deadspace than other configurations.

In illustrative embodiments, the paddle 32 has a longitudinal axis 52defined by its length. As shown in FIG. 2, the bag 28 also has alongitudinal axis 29 running through its length (e.g., an axis runningthrough input valve 21A and output valve 21B). In illustrativeembodiments, the longitudinal axis 52 of the paddle 32 is aligned withthe longitudinal axis 29 of the bag 28 to inhibit the formation of deadspace that may otherwise form during compression of the bag 28. Byarranging the paddle 32 and the bag 28 so that their longitudinal axes29 and 52 are substantially aligned, the bag 28 is more evenlycompressed.

In some embodiments, the longitudinal axes 29 and 52 are less than 90degrees offset from one another. Preferably, the longitudinal axes 29and 52 are no more than 45 degrees offset from one another. In someembodiments, the longitudinal axes 29 and 52 are no more than 30 degreesoffset from one another. In some embodiments, the longitudinal axes 29and 52 are less than 10 degrees offset from one another. Additionally,to assist with reduction of dead space, in some embodiments, the lengthof the paddle 32 is at least 40% of the length of the body of the bag28. More preferably, the length of the paddle 32 is greater than 50%,60%, 70%, or 80% of the length of the body of the bag 28.

FIG. 4 schematically shows a block diagram of a system 100 forventilation in accordance with illustrative embodiments of theinvention. Air enters the system 100 and optionally go through a filter,which filters contamination such as dust. The air may be received fromthe environment, and/or through connected gas cylinders that arecommercially available (e.g., through commercial entities such as Airgasor equipment such as air compressors). In illustrative embodiments, theair may pass through input valve 21A. The air then reach the insides ofthe body of the bag 28. The bag 28 is compressed by the paddle 32, whichcauses the air to flow through the output valve 21B of the bag 28towards the mask 26.

In some embodiments, the paddle 32 has a convex shape. Specifically, asdiscussed previously, the paddle 32 may have a convex contact surface50. Additionally, the paddle 32 may be oriented relative to the bag 28such that their longitudinal axes 29 and 52 are substantially aligned.Thus, as the actuator (e.g., the motor 40) causes the strap 43 totighten, the paddle 32 compresses the bag 28 and the bag 28 deforms in apredictable manner. The inventors discovered that the arrangement of theconvex paddle 52 aligned with the longitudinal axis of the bas 28minimizes dead space and allows for precision control of the volumeexpelled. Furthermore, in illustrative embodiments, the strap 34provides a mechanically robust system 100 that provides precisioncontrol of the speed and volume of compression.

As the air flows out of the bag 28, it flows through the pressure sensor44, the flow rate sensor 42, and/or the oxygen sensor 46. The pressuresensor 44, the flow rate sensor 42, and/or the oxygen sensor 46 send asignal to the controller 42. The controller 42 controls, among otherthings, the movement of the actuator based on the input values set inthe beginning (e.g., by the user 20 or by automatically by the device12). The input values include, for example, tidal volume, pressure,volume limit, peak pressure, I:E ratio, inspiratory time, and breathingrate. These values are evaluated by the encoder and the controller 54 tomove the actuator.

The signals are fed back to the controller 54, as is described furtherbelow. The controller 54 may evaluate the signals and adjust themovement of the actuator, and thus, the amount of air output by the bag28. The quantified air is passed through the sensors 42, 44, and/or 46optionally to a second filter, and then to a breathing tube circuit 22,which is connected to the patient 13. The controller 54 also providesvalues for flow rate, peak pressure, minute volume and oxygen saturationover time, which can be displayed in a graphical or numeric form on thedisplay, the user interface of the device 12, and/or on the mobile app.

In some embodiments, the sensors 42-46 may send a message to thecontroller 54, the display, and/or the alarm. The message may betriggered by a sensor measurement that is not in accordance with theprescribed value for the respiratory parameter (e.g., pressure orvolume). The controller 54 may then adjust compression of the bag 28 bythe paddle 32 to put the respiratory parameter in accordance with theprescribed value.

FIG. 5 schematically shows details of the controller 54 that receivesfeedback from the one or more sensors 42 and 44, and that controls theoutput of the motor 40 in accordance with illustrative embodiments ofthe invention. The controller 54 is configured to, among other things,control the output of the motor 40. To that end, the controller has anactuator control module 53. The actuator control module 53 controls thetorque, velocity, position, and/or speed output of the motor 40. Thus,the actuator control module 53 indirectly controls the pressure and flowrate output by the bag 28 (the motor 40 controls position and speed ofthe paddle 32).

The controller also has a memory 55. The memory 55 may store informationrelating to the input parameters, the data received from the sensorinterface, and/or formulas used to calculate respiratory parameters.

The controller 54 controls the motor 40 in accordance with prescribedvalues for various respiratory parameters. To that end, the controller54 has a user interface engine 56, which may receive inputs, forexample, from the physical user interface 23. Additionally, the userinterface engine 56 may communicate with the user interface 23 and/orthe display 19. For example, the user interface engine 56 may receive amessage from the signal interface 59 indicating that one or more of thesensors 42, 44, and/or 46 is detecting an out of parameter condition.For example, the oxygen sensor 46 may detect that the oxygen is too low.As an additional example, the pressure sensor 44 may detect that thepressure is too high. The user interface engine 56 may send an alarm tothe physical user interface 23, the electronic mobile device 19, oranother display, informing the user 20 that the out of condition stateexists. Additionally, in some embodiments, the out of parametercondition may be sent to the actuator control module 53. The actuatorcontrol module 53 may adjust the operation of the actuator (e.g., bystopping the compression of the bag 28 completely).

The user interface engine 56 receives the user 20 selection of one ormore respiratory parameters, including Output Volume, Pressure Limit,Breathing rate, Inhalation to exhalation ratio, and/or inspiratory time.The user 20 may enter specific values for each of the respiratoryparameters, and the motor 40 is correspondingly controlled to output airfrom the bag 28 in accordance with those parameters.

Alternatively, the user 20 may enter information about the patient 13(e.g., height, weight, sex), and a parameter calculation module 58 maycalculate appropriate respiratory parameters for the patient 13. To thatend, the calculation module 58 may communicate with the memory to accessformulas known in the literature.

The controller 54 also has a calibration module 57. As will be describedfurther below, with reference to FIG. 6, the device 12 may use acalibration process. The calibration module receives respiratoryparameters and/or a ventilation mode from the user interface engine 56.The calibration module 57 instructs the actuator control module 53 tobegin ventilation. A sensor interface 59 interfaces with the varioussensors 42, 44, and/or 46, and receives data about the output air (e.g.,pressure, flow rate, oxygen level, etc.). The calibration module 57determines if the output air is in compliance with prescribed values forthe respiratory parameters. If not, the calibration module 57 sends asignal to the actuator control module 53 to adjust the signal sent tothe motor 40.

Each of the above-described components is operatively connected by anyconventional interconnect mechanism. FIG. 5 simply shows a bus 51communicating each of the components. Those skilled in the art shouldunderstand that this generalized representation can be modified toinclude other conventional direct or indirect connections. Accordingly,discussion of a bus is not intended to limit various embodiments.

Indeed, it should be noted that FIG. 5 only schematically shows each ofthese components. Those skilled in the art should understand that eachof these components can be implemented in a variety of conventionalmanners, such as by using hardware, software, or a combination ofhardware and software, across one or more other functional components.For example, the actuator control module 53 may be implemented using aplurality of microprocessors executing firmware. As another example, thecalibration module 57 may be implemented using one or more applicationspecific integrated circuits (i.e., “ASICs”) and related software, or acombination of ASICs, discrete electronic components (e.g.,transistors), and microprocessors. Accordingly, the representation ofthe components in a single box of FIG. 5 is for simplicity purposesonly. In fact, in some embodiments, the actuator control module 53 isdistributed across a plurality of different machines—not necessarilywithin the same housing or chassis. Additionally, in some embodiments,components shown as separate (such as the calculation module 58 and thecalibration module 57) may be replaced by a single component.Furthermore, certain components and sub-components in FIG. 5 areoptional. For example, some embodiments may not use the parametercalculation module 58.

It should be reiterated that the representation of FIG. 5 is asignificantly simplified representation of the ventilation controller54. Those skilled in the art should understand that such a device mayhave other physical and functional components, such as centralprocessing units, other packet processing modules, and short-termmemory. Accordingly, this discussion is not intended to suggest thatFIG. 5 represents all of the elements of the ventilation controller 54.

FIG. 6 shows one embodiment of a process 600 of ventilating the patient13 in accordance with prescribed values for respiratory parameters. Itshould be noted that this process is substantially simplified from alonger process that normally would be. As such, the process may haveadditional steps that are not discussed. In addition, some steps may beoptional, performed in a different order, or in parallel with eachother. For example, step 602 may come after step 608. As anotherexample, step 620 may start after step 608. Furthermore, some of thesesteps may be optional in some embodiments. Accordingly, discussion ofthis process is illustrative and not intended to limit variousembodiments of the invention. Accordingly, the process 600 is merelyexemplary of one process in accordance with illustrative embodiments ofthe invention. Those skilled in the art therefore can modify the processas appropriate.

The process 600 begins at step 602, which couples the output of thedevice 12 with the patient's 13 respiratory tract. Specifically, theoutput valve 21B shown in FIG. 1 is securely connected via the tubing 22and the mask 26 over the patient's 13 mouth and nose. The process thenproceeds to step 604, which receives the respiratory parameters. Asmentioned previously, the user may manually enter values for therespiratory parameters through the user interface 23, and/or theparameter calculation module 58 may generate values for the parametersafter providing information about the patient 13. In order to receivethe respiratory parameters, the device 12 may be powered on using the onand off switch (not shown). The user interface 23 may comprise an LCDscreen that displays instructions. Additionally, or alternatively, theuser interface 23 may be on a user's mobile device (e.g., smartphone).In some embodiments, step 602 may come after the device 12 iscalibrated.

The user 20 inputs the respiratory parameters (e.g., the user 20 mayrotate the knob(s) to adjust the inputs) based on the patient's 13clinical state. The respiratory parameters may include, for example,tidal volume, peak pressure, breathing rate, and/or I:E ratio. Inillustrative embodiments, the user 20 may input one or more respiratoryparameters including: tidal volume, pressure, volume limit, peakpressure, I:E ratio, inspiratory time, and/or breathing rate of theoxygen and/or the air flowing through the output valve 21B to thepatient 13. For example, the user 20 may input tidal volume.Alternatively, the user 20 may input the tidal volume and the pressure.Furthermore, the user 20 may input all of the above describedrespiratory parameters. Specifically, in some embodiments the user 20may set the tidal volume from between about 0 and about 700 mL, peakpressure from between about 0 and about 50 mm H2O, breathing rate fromabout 0 to about 35 breaths/min. The user 20 may then confirm thesettings by pressing a confirmation button.

The process 600 then proceeds to step 606, where the user 20 selects theventilation mode. The user 20 may select between volume controlledventilation, which compresses the bag 28 to deliver air at a selectedvolume, and/or pressure controlled ventilation, which compresses the bag28 to deliver air at a selected pressure. Within volume controlledventilation, there is an additional option to set control ventilation,where the device 12 delivers constant parameters if the patient 13 isnot breathing on their own. Alternatively, under volume controlledventilation, the user 20 may select assist-control ventilation, wherethe device 12 synchronizes its compressions with the patient's 13 ownbreathing rhythm

In pressure control ventilation mode, the user 20 provides a prescribedvalue for pressure of the airflow output by the bag 28. The pressuresensor # measures the output pressure to confirm that it is inaccordance with the prescribed value. In some embodiments, theprescribed value may be a range or a target value having a built in+/−tolerance. Furthermore, pressure control ventilation may ask the user20 to select a peak tidal volume and/or peak volume limit.

Volume controlled ventilation delivers a precise amount of volume perinspiration. For example, volume controlled ventilation mode adjusts theoutput tidal volume (e.g., 400 mL), and allows the user 20 to set limitsfor peak pressure, breathing rate (e.g., how many breaths in a minute),inspiratory time (e.g., how long to deliver the 0-400 mL breathing),and/or I:E ratio.

The system may also be configured to operate in a pressure controlledventilation mode. Pressure controlled ventilation mode adjusts thepressure, tidal volume limit, breathing rate, and inspiratory time.

In control ventilation mode, the device 12 is configured to compress thebag 28 on a repeating time cycle. The controller 54 receives the inputrespiratory parameter values. In some embodiments, the controller 54assigns a specific distance for the actuator to move based on acalibrated zero value (e.g., using the actuator control module 53).Additionally, the controller 54 may pre-select the time between cycleswhere the actuator sits at the zero (e.g., bag 28 uncompressed)position. Furthermore, the controller 54 may monitor the speed of theactuator for inhale and exhale cycle over time (e.g., using thecalibration module 57). In addition, the controller 53 may take receivereal-time data from the sensors through the sensor interface 59. Thereal-time sensor data may be sent to the actuator control module 53 andused to adjust the compression parameters (e.g., speed) to produce theprescribed flow rate and pressure rate (e.g., by communicating thecalibration module 57 with the sensor interface 59 and/or memory 54).

In a similar manner to control ventilation, in assist controlventilation mode the device 12 may also be configured to compress thebag 28 on a repeating time cycle. Accordingly, the patient 13 may beventilated at a particular breathing rate. However, assist controlventilation may also be trigged by the patient's 13 attempt to inhale ontheir own. This may find clinical applications, for example, when thepatient 13 is not totally sedated. In such a circumstance, the patientmay have consciousness and may breathe on their own accord. Illustrativeembodiments may provide additional respiratory support that matches thepatient's 13 breathing rate. This provides enhanced comfort to thepatient 13. Additionally, if the patient 13 cannot breath, or stopsdrawing breath, on their own, the device 12 may ventilate the patient 13at the prescribed breathing rate (e.g., selected by the user 20). Thus,in illustrative embodiments, assist control ventilation mode may sendthe patient 13 a new breath unless the patient 13 overrides it.

In some embodiments, assist control ventilation is triggered when the

patient attempts to inhale while the actuator is at the zero position(e.g., bag 28 is uncompressed) and there is time left before the cyclebegins. In assist control ventilation, the sensor continuously monitorsfor a backflow reading from outlet side (i.e., from the patient 13). Ifthe patient 13 attempts to inhale the values for flow and pressure gobeyond the noise threshold and the reading is recorded by the controller56. The controller 56 may then reset the actuation cycle andappropriately change the time delay between each cycle depending on thepatient's 13 inhalation time. The controller 56 then rests the actuationcycle and appropriately changes the time delay between each cycledepending on the patient's 13 inhalation time.

In both assist control ventilation mode and control ventilation mode,the user 20 provides a prescribed value for volume of the air output bythe bag 28. The flow rate sensor 42 measures the output air to confirmthat it is in accordance with the prescribed value. In some embodiments,the prescribed value may be a range or a target value having a built in+/−tolerance. Furthermore, assist control ventilation mode and controlventilation mode may ask the user 20 to select a peak pressure.

Steps 608-614 calibrate the device 12 when it is initially operatedand/or when the values for one or more respiratory parameters arechanged. Additionally, this calibration process may occur passivelyduring the operation of the device 12, even after it has beencalibrated, to ensure that the device 12 is operating in accordance withthe intended respiratory parameters.

At step 608 ventilation begins. Illustrative embodiments compress thebag 28 so that it deforms and collapses in on itself. The inventorsdiscovered that driving a convexly shaped paddle 32 optimized theevacuation of the air volume inside the bag 28. Specifically,illustrative embodiments orient the longitudinal axis 52 of the paddle28 substantially in parallel to the longitudinal axis 29 of the bag 28.The strap 34 is also partly wrapped around the body of the bag 28.Accordingly, illustrative embodiments aid in consistent and precisedelivery of the desired volume at a set pressure while minimizing deadspace.

The controller 54 sends a signal to the motor 40 that winds the strap 34around the spindle 36 at a predetermined velocity. The power deliveredto the spindle 36 is governed by the flow rate measured during thisstep, i.e., if low flow rate is detected, the motor 40 is given morepower. Conversely, if high flow is detected the power is reduced (e.g.,tapered off gradually). Once the target output volume is achieved, thevelocity profile and target positions (amount of rotation required bythe motor 40) are recorded as the base compression profile for the startof ventilation. These may be stored in the memory 55 of the controller54.

After the settings are chosen, the device 12 completes at least onecycle to calibrate based on inputs. For calibration, the actuator exertsforce on the bag 28 until a slight flow of air and/or oxygen is detectedby the flow rate sensor 42 and/or pressure sensor 44.

At step 610, the air pressure and/or flow rate data from the air comingout of the bag 28 is received by the controller 54. As describedpreviously, the device 12 may have pressure sensor 44 and/or flow ratesensor 42. These sensors 42 and 44 measure the pressure and flow rate,respectively, and provide that data to the controller 54. The device 12uses dynamic pressure and flow sensor data that is collected in realtime to adjust the compression of the bag 28. This data is forwarded tothe controller 54. Illustrative embodiments may review data from thelast few compression cycles to determine whether the device 12 reaches asteady state governed by the prescribed respiratory parameters (e.g.,input by the user or calculated by the calculation module 58).

The process then moves to step 612, which asks whether the pressure, theflow rate, and/or the respiratory parameters are in compliance with theprescribed values. If the input parameters (e.g., tidal volume, peakpressure, breathing rate, etc.) or external variables (e.g.,resistance/compliance of the patient's lungs) are causing any of thevariables to be out of compliance with the prescribed values, theprocess 600 moves to step 614.

At step 614, the process 600 compensates for the variance in thepressure, the flow rate, and/or the respiratory parameters by adjustingthe speed and/or distance that the actuator moves. For example, thecontroller 54 may send a signal to the motor 40 requiring that theactuator stroke should be increased.

As an example of volume control adjustment, the device 12 may be set toachieve a tidal volume of 400 mL with every inspiration of the patient13. After calibration, the device 12 may output the tidal volume of 400mL. If the patient 13 changes their position on the hospital bed (e.g.,as the anesthesia begins to wear off), there may be an increasedresistance in the lungs. Accordingly, the actual volume of air thatreaches the patient's 13 lungs drops below the desired parameter due tothe increased resistance. The feedback mechanism of illustrativeembodiments of the invention uses sensors to detect the decrease, andinstructs the actuator to move faster and/or more forcefully inreal-time to meet the tidal volume goal. This dynamic adjustment of theactuator may continue during the current and future breathing cycles.

As an example of pressure control adjustment, the device 12 may be setto reach a desired pressure of 25 mm H2O. In order to achieve thisvalue, the actuator dynamically course-corrects its velocity throughoutthe duration of the compression to deliver 22 mm H2O.

After calibration is complete, the user interface 23 (e.g., LCD) mayinstruct the user 20 to put the mask on or connect the endotracheal tubeto the patient 13, if it is not already on the patient 13. The device 12then begins to deliver the desired amount of air and/or oxygen to thepatient 13 in accordance with the prescribed respiratory parameters. Ifthe settings need to be changed, the user 20 may pause the device 12 andre-adjust the input settings. The user 20 may then re-start the device12, which delivers the new levels of desired air and/or oxygen.

If the pressure, the flow rate, and/or the respiratory parameters are incompliance with the prescribed parameters, the process moves to step616, where ventilation is continued until the user 20 stops the device12.

Optionally, the process may move to step 618, where the device 12 sendsa signal (e.g., to a mobile device application) where the flow rate andpressure data are recorded and displayed over time. This provides users20 with information relating to the ventilation delivery pattern of thepatient 13. To turn the device 12 off, the user takes themask/endotracheal tube off the patient and turns off the power switch.

Additionally, the process may optionally move to step 620. In case thevalues of the desired air and/or oxygen delivered deviates, step 620causes alarms to be triggered to notify the user 20. These alarms willtrigger if the readings are, for example, above and/or below tidalvolume input and peak pressure. Although shown near the end of process600, steps 618-620 may be ongoing from the beginning of the process.

A person of skill in the art should understand that illustrativeembodiments provide a number of advantages. For example, illustrativeembodiments provide superior control over the ventilation delivered tothe patient by the bag 28. Specifically, feedback sensors 42 and 44 forpressure and flow rate are detected and used to adjust the tidal volume,peak pressure, breathing rate and/or I:E ratio to match the selectedinputs. Illustrative embodiments also increase patient safety by usingalarm sensors to detect whether an accurate amount of air and/or oxygenis delivered to the patient.

Illustrative embodiments provide a further advantage in that theyintegrate with equipment already in common use in the hospital. In someembodiments, the output valves are able to integrate with both ends ofthe breathing circuit and mask, which allows the device to be easilyused in a hospital setting. Furthermore, illustrative embodiments areportable. To that end, the device may be formed from light materials,including plastics, and the components may be compactly arranged.

Other advantages of illustrative embodiments include simplefunctionality. For example, the input controls may include three knobs,one confirmation button, and one slider switch to change betweenventilation modes and a power button. Furthermore, a LCD may be placedon the device 12 to display real time readings. Illustrative embodimentsare also user friendly. For example, two back doors allow for easyaccess to internal components, including the bag 28 and the batteries.Furthermore, many of the components of the device are available in lowresource settings, such as the bag 28, batteries, and other internalcomponents.

Yet another advantage of illustrative embodiments is remote monitoringof ventilation data. This is achieved, for example, via a mobileapplication. Illustrative embodiments have a graphical display of data,such as tidal volume, I:E ratio, peak pressure, breathing rate, % oxygensaturation and minute volume ventilation. This provides real timemonitoring of the patient's 13 condition to the doctor and is especiallyuseful in hospitals that are understaffed.

Various embodiments of the invention may be implemented at least in partin any conventional computer programming language. For example, someembodiments may be implemented in a procedural programming language(e.g., “C”, “Python”, etc.), or in an object oriented programminglanguage (e.g., “C++”). Other embodiments of the invention may beimplemented as preprogrammed hardware elements (e.g., applicationspecific integrated circuits, FPGAs, and digital signal processors), orother related components.

In an alternative embodiment, the disclosed apparatus and methods (e.g.,see the various flow charts described above) may be implemented as acomputer program product for use with a computer system. Suchimplementation may include a series of computer instructions fixedeither on a tangible, non-transitory medium, such as a computer readablemedium (e.g., a diskette, CD-ROM, ROM, or fixed disk). The series ofcomputer instructions can embody all or part of the functionalitypreviously described herein with respect to the system.

Those skilled in the art should appreciate that such computerinstructions can be written in a number of programming languages for usewith many computer architectures or operating systems. Furthermore, suchinstructions may be stored in any memory device, such as semiconductor,magnetic, optical or other memory devices, and may be transmitted usingany communications technology, such as optical, infrared, microwave, orother transmission technologies.

Among other ways, such a computer program product may be distributed asa removable medium with accompanying printed or electronic documentation(e.g., shrink wrapped software), preloaded with a computer system (e.g.,on system ROM or fixed disk), or distributed from a server or electronicbulletin board over the network (e.g., the Internet or World Wide Web).In fact, some embodiments may be implemented in a software-as-a-servicemodel (“SAAS”) or cloud computing model. Of course, some embodiments ofthe invention may be implemented as a combination of both software(e.g., a computer program product) and hardware. Still other embodimentsof the invention are implemented as entirely hardware, or entirelysoftware.

Disclosed embodiments, or portions thereof, may be combined in ways notlisted above and/or not explicitly claimed. In addition, embodimentsdisclosed herein may be suitably practiced, absent any element that isnot specifically disclosed herein. Accordingly, the invention should notbe viewed as being limited to the disclosed embodiments.

The embodiments of the invention described above are intended to bemerely exemplary; numerous variations and modifications will be apparentto those skilled in the art. Such variations and modifications areintended to be within the scope of the present invention as defined byany of the appended claims.

What is claimed is:
 1. A system for ventilating a patient comprising: aflexible bag having a flexible central portion, a first rigid end, and asecond rigid end, the flexible bag configured to be inflated through aninput valve at the first rigid end that allows oxygen and/or air to flowinto the bag, the bag further configured to be deflated through anoutput valve at the second rigid end that allows the oxygen and/or theair to flow out of the bag; an actuator including a convex contactsurface configured to compress the bag to cause the oxygen and/or theair to flow out of the output valve in accordance with prescribed valuesfor one or more respiratory parameters, the one or more respiratoryparameters including tidal volume, pressure, volume limit, peakpressure, I:E ratio, inspiratory time, and/or breathing rate of theoxygen and/or the air flowing through the output valve to a patient,wherein the actuator includes a flexible portion coupled with the convexcontact surface, the flexible portion also compressing the bag; acontroller configured to control the position of the actuator and/or thespeed at which the actuator moves in accordance with the prescribedvalues for the one or more respiratory parameters; a pressure sensorcoupled to the output valve and configured to determine the pressure ofthe oxygen and/or the air flowing through the output valve, the pressuresensor further configured to send a pressure signal to the controller; aflow rate sensor coupled to the output valve and configured to determinethe flow rate of the oxygen and/or the air flowing through the outputvalve, the flow rate sensor further configured to send a flow ratesignal to the controller; the controller configured to receive thepressure signal and/or the flow rate signal, and to determine whetherthe output tidal volume, pressure, volume limit, peak pressure, I:Eratio, inspiratory time, and/or breathing rate are in accordance withthe prescribed values, the controller further configured to adjust theposition of the actuator and/or the speed at which the actuator moves soas to adjust the output tidal volume, peak pressure, and/or breathingrate to be in accordance with the prescribed values for the one or morerespiratory parameters.
 2. The system as defined by claim 1, wherein thebag has a longitudinal axis, and the convex contact surface isconfigured to extend along the longitudinal axis.
 3. The system asdefined by claim 1, wherein the actuator comprises a spindle that isconfigured to tighten a strap, the strap being coupled to a paddlehaving the convex contact surface.
 4. The system as defined by claim 3,wherein a first end of the strap is fixed, and a second end of the strapis movable, the paddle being positioned between the first end and thesecond end.
 5. The system as defined by claim 3, wherein the bag iscompressed between the paddle and a flat surface.
 6. The system asdefined by claim 5, wherein the flat surface is a fixed surface.
 7. Thesystem as defined by claim 1, further comprising an oxygen sensorcoupled to the output valve and configured to determine the oxygenconcentration flowing through the output valve, the oxygen sensorfurther configured to send an oxygen signal to the controller, thecontroller (1) determining from the oxygen signal whether the patientneeds more oxygen, and (2) providing a message to a user interface totitrate oxygen if the user needs more oxygen.
 8. The system as definedby claim 1, wherein the controller is configured to receive a selectionof a pressure control mode or a volume control mode, the pressurecontrol mode including a prescribed value for the pressure, and aprescribed volume limit, the volume control mode including a prescribedvalue for the tidal volume, and a prescribed limit for the peakpressure.
 9. The system as defined by claim 8, wherein (a) an alert istriggered and/or (b) the actuator ceases ventilation, when theprescribed limit is exceeded.
 10. A method of ventilating a patientcomprising: controlling an actuator having a convex contact surface, anda flexible portion coupled with the convex contact surface, inaccordance with a prescribed value for a respiratory parameter, tocompress an inflatable bag having a flexible central portion and tworigid ends, to cause oxygen and/or air to flow out of an output valve ofthe bag, the respiratory parameter being tidal volume, pressure, volumelimit, peak pressure, I:E ratio, inspiratory time, and/or breathing rateof the oxygen and/or the air flowing through the output valve; sensingthe pressure flowing through the output valve, and sending a pressuresignal to the controller; sensing flow rate through the output valve,and sending a flow rate signal to the controller; adjusting thecompression of the actuator as a function of the flow rate signal and/orthe pressure signal to adjust the tidal volume, pressure, volume limit,peak pressure, I:E ratio, inspiratory time, and/or breathing rate to bein accordance with the prescribed value.
 11. The method of claim 10,wherein the actuator is coupled to a paddle having the convex contactsurface.
 12. The method of claim 10, wherein the actuator is coupled toa paddle having a longitudinal axis, the method further comprisingsubstantially aligning the longitudinal axis of the paddle with alongitudinal axis of the bag.
 13. The method of claim 10, whereinadjusting the compression of the actuator is one of adjusting theposition of the actuator and/or the speed at which the actuator moves.14. The method of claim 10, wherein the actuator comprises a spindle,the spindle being configured to tighten a strap that is coupled to thepaddle.
 15. A non-transitory computer-readable medium encoded withinstructions that, when executed by a processor, establish processes forperforming a computer-implemented method of activating an actuator toventilate a patient, the processes comprising: receiving an input of aprescribed value for a respiratory parameter; controlling an actuatorcoupled to a paddle having a convex contact surface to compress aninflatable bag to cause oxygen and/or air to flow out of an output valveof the bag in accordance with the prescribed value for the respiratoryparameter, the actuator including a flexible portion coupled with theconvex contact surface, the flexible portion also compressing the bag;interfacing with (1) a pressure sensor that measures the pressure of theoxygen and/or the air flowing through the output valve, and/or (2) aflow rate sensor coupled to the output valve and configured to determinethe flow rate of the oxygen and/or the air flowing through the outputvalve; receiving a pressure signal from the pressure sensor and/or aflow rate signal from the flow rate sensor; adjusting the controlling ofthe actuator to compress the bag to put the output value for therespiratory parameter in accordance with the prescribed value.
 16. Thenon-transitory computer-readable medium of claim 15, wherein therespiratory parameter is tidal volume, pressure, volume limit, peakpressure, I:E ratio, inspiratory time, and/or the air flowing throughthe output valve.
 17. The non-transitory computer-readable medium ofclaim 15, wherein the actuator is coupled to a paddle having alongitudinal axis, further comprising substantially aligning thelongitudinal axis of the paddle with a longitudinal axis of the bag. 18.The non-transitory computer-readable medium of claim 15, wherein theactuator comprises a spindle, the spindle being configured to tighten astrap that is coupled to the paddle.
 19. The non-transitorycomputer-readable medium of claim 15, wherein adjusting the compressionof the actuator is one of adjusting the position of the actuator and/orthe speed at which the actuator moves.